Asymptotic theory for ignition and extinction in droplet burning

The quasi-steady diffusion flame structure in droplet burning is analysed, in the limit of large activation energy, for a one-step Arrhenius reaction in the gas phase. The characteristic ignition-extinction S-shaped curve is produced with segments of it corresponding to a nearly frozen flow regime, a partial burning regime, a premixed flame regime, and a nearly equilibrium regime. Critical Damköhler numbers for ignition and extinction, as well...